Method of forming sheet metal articles



Dec. 21, 1937. AM R ER 2,102,732

METHOD OF FORMING SHEET METAL ARTICLES Filed Jan. 11, 1936 //V VE/VTO/i /I A. MORBfRG 4Q Mm Patented Dec. 21, 1937 PATENT OFFICE METHOD OF FORMING SHEET METAL ARTICLES Ivar A. Morberg, Chicago, 111., assis'nor to Western Electric Company, Incorporated, New York, N. Y., a corporation of New York Application January 11, 1936, Serial No. 58,635

3 Claims.

- This invention relates to a method of forming sheet metal articles; and more particularly to a method of forming the lower housings-of telephone coin collectors.

It is an object of the present invention to provide an inexpensive method of producing a strong and durable structure for enclosing coin receptacles.

In accordance with one embodiment of the invention as applied to the lower housing of telephone coin collectors which houses the coin receptacle, a blank is cut from sheet metal stock and drawn to a hollow substantially rectangular configuration intended to serve as the front and portions of the side, top and bottom walls of the lower housing. The blank is then perforated --to form a door opening and partially form a coin chute opening, whereupon the edges of the door opening are drawn backwardly out of the plane of the front of the rectangular detail and the coin chute opening is sheared and the side of the sheared portion partially formed out of the plane of said front. In the next stepthe edges of the door opening are trimmed to remove some of the excess metal, and finally the sheared portion of the front is bent at right angles to the front, and the edges of the door opening swaged to form a seat for the door. After the front half of the housing is formed in this manner, it is welded to the rear portion of the coin box.

A better understanding of the invention may be had by reference to the following description when considered in conjunction with the accompanying drawing, wherein Fig. 1 is an isometric projection of the lower housing of a telephone coin collector having a front portion formed in accordance with the present invention;

Fig. 2 is an isometric projection of a blank sheared from stock and formed in accordance with the first step of the invention, parts being broken away to more clearly illustrate the configuration of the blank, and

Figs. 3, 4 and 5 are views similar to Fig. 2 illustrating the successive steps in forming the front half of the coin box.

Referring now to the drawing wherein like reference characters indicate the same parts throughout the several views, particular reference being had to Fig. 1 wherein a lower housing ill for a telephone coin collector comprises a' front portion and a rear portion indicated generally by the numbers H and I2, respectively. When this housing is in use it is secured to a base or back plate and encloses a coin receptacle, a door being inserted in the opening l3 in the front portion II. The base or back plate, door, and upper portion which supports the telephone apparatus have not been shown since they are well known and do not form part a flat top 25, a front wall 26 and an angularly disposed portion 21, all formed from a single sheet of metal. The front portion also includes a bottom 28 and sides 29 and 30 and has in addition to the door opening l3, a coin chute opening 3| through which coins, which have. been deposited by a user, may be withdrawn when a call made by the user is not completed.

The present invention is directed to a method of forming housings of this type and relates particularly to the method of forming the front portion II. In the first step of the invention a substantially rectangular box-like blank as illustrated in Fig. 2 is simultaneously punched from sheet metal and drawn to form the top 25, front wall 26, angularly disposed portion 21, bottom 28 and sides 29 and 30. After the blanking and drawing operation the edges 35, 36, 31 and 38 of the top 25, bottom 28 and sides 29 and 30, respectively, are trimmed to remove any rough edges formed in the drawing operation and to flatten the surfaces so that, when the front portion II and rear portion l2 are assembled there will be no cracks between them indicating the joint.

In Fig. 3, the next step of the method is illustrated which comprises perforating two holes indicated by the numerals 39 and 40. The hole 40 will later be formed to receive the door (not shown) and the hole 39 which is a comparatively narrow slot will later be formed to comprise the coin chute opening 31.

After the coin chute opening 3| has thus been partially made as indicated at 39 and the door opening H! has been partially made as indicated at 40 in Fig. 3, a preliminary drawing operation is performed on the edges of the hole 40 and simultaneously a shearing operation is performed to enlarge the hole 39. As shown in Fig. 4 the preliminary step to the final operation of form;

ing the front portion ll.

The final step in forming the frontportion ll.

comprises completing the bending of the portion indicated at 43 (Fig, 4) to a plane at right angles to the plane of the front wal1'26 as shown at 45 and swaging the edges of the door opening l3 (Fig. 5). The final step results in forming the seat for the door with a flat surface 46 against which the door will rest and also results in thickening and strengthening the seat as shown at 41 thereby making it more difficult to force the door open after. it has been locked in place. Simultaneously with the swaging of the edges of the door opening an embossing 48 (Fig. 1) is formed in the front wall 26.

If any of the hereinbefore described operations have distorted or roughened the edges 36, 31, and 38, an additional trimming operation may be performed to straighten the edges. After the front portion l I has thus been formed it may be secured to the rear portion l2 by welding a strip 50 to it and to the rear portion as shown in Fig. .1 and a partition 5| may be secured to thebottom of the rear portion 12 and to the portion of the front wall 26 which is bent at right angles to the front wall and indicated at (Figs. 1 and 5) What is claimed is: I 1. The method of forming the front of a coin box for telephone pay stations which comprises termined line.

forming a blank having a front wall and top, bottom and side flanges, perforating two openings in the front wall of the blank, enlarging one of said openings by shearing and folding the metal adjacent thereto at an angle to the front wall, and drawing the metal adjacent the edges of the second opening out of theplane of thefront wall, and. swaging the edges of said second opening to form aldoor seat and to thicken the material adjacent the edges along a prede- 2. The method of forming the front of a coin 7 box for telephone pay stations comprising forming a rectangular blank having a front wall and top, bottom and side flanges, perforating two 3. The method of forming the front of a coin box for telephone pay stations comprising forming a rectangular blank having a front wall and top, bottom and side flanges, perforating two openings in the front wall, enlarging one of said openings by shearing and folding the metal adjacent thereto at an angle to the plane of the front wall, drawing the metal adjacent the edges of the other opening out of the plane of the front wall, and simultaneously swaging the edges of the last mentioned hole to provide a door seat and again bending the metal previously bent to a position at right angles to the plane of the front wall. v

' IVAR A. MORBERG.

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